[proxies] allow duplicate keys for [[OwnPropertyKeys]] trap.

src/debug/debug-scopes.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_DEBUG_DEBUG_SCOPES_H_
 #define V8_DEBUG_DEBUG_SCOPES_H_
 
 #include "src/debug/debug-frames.h"
 #include "src/frames.h"
 
@@ skipping 121 matching lines @@
   bool SetContextLocalValue(Handle<ScopeInfo> scope_info,
                             Handle<Context> context,
                             Handle<String> variable_name,
                             Handle<Object> new_value);
 
   void CopyContextLocalsToScopeObject(Handle<ScopeInfo> scope_info,
                                       Handle<Context> context,
                                       Handle<JSObject> scope_object);
   bool CopyContextExtensionToScopeObject(Handle<JSObject> extension,
                                          Handle<JSObject> scope_object,
-                                         JSReceiver::KeyCollectionType type);
+                                         KeyCollectionType type);
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(ScopeIterator);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_DEBUG_DEBUG_SCOPES_H_